<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./lib/vue.js"></script>
</head>
<body>
<div id="root">
    <button @click="fn">点我</button>
    <hr/>
    <child/>
</div>
</body>
<script>
    new Vue({
        el: '#root',

    })
</script>
</html>